BALSASUD® Core is the finest end-grain balsa wood core material in the market, ideal for sandwich construction. It has remarkable physical properties, starting with its outstanding strength-to-weight ratios (high shear and compression strength). It is an all-natural and renewable resource coming from Ecuador. It has exceptional fatigue and impact resistance properties. And it provides phenomenal sound and thermal insulation. In addition, it is a natural fire-retardant material.